Vascular Sealing Device and Method Using Clot Enhancing Balloon and Electric Field Generation

ABSTRACT

An apparatus and method for closing an opening in a blood vessel wall is disclosed. The apparatus includes at least one member which is extended through a tissue tract formed through the epidermis and subcutaneous layer of skin and through the opening in the blood vessel. The member includes a proximal end and a distal end with the distal end being positionable proximate to the opening in the blood vessel wall. A positive electrode is positioned next to the distal end with a negative electrode being positioned next to the proximal end When the electrodes are energized an electric field is created therebetween, blood cells are attracted to the positive electrode, and a thrombus is formed at the opening in the blood vessel wall. The member may include a balloon at the distal end to temporarily occlude blood flow from the blood vessel to the tissue tract to facilitate formation of the thrombus. In addition, the shape of the balloon may be tailored to facilitate the formation of the thrombus including, but not limited to, the creation of pockets and self-supporting balloons

CROSS-REFERENCE TO RELATED APPLICATION

This application is a non-provisional patent application claimingpriority under 35 USC § 119(e) to U.S. provisional patent applicationSer. No. 60/888,202 filed on Feb. 5, 2007.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to medical devices and, moreparticularly, relates to apparatus and methods for closing openings inblood vessels.

BACKGROUND OF THE DISCLOSURE

In many medical procedures, such as balloon angioplasty and the like, itis known how to create an opening in a blood vessel, known as anarteriotomy, to allow for the insertion of various medical devices whichcan be navigated through the blood vessel to the site to be treated.Typically, the opening is formed in the femoral artery at a pointproximate the groin and a series of medical devices are inserted insequence. For example, a guide wire may first be inserted through thetissue tract created between the skin or the epidermis of the patientdown through the subcutaneous tissue and into the opening formed in theblood vessel The guide wire is then navigated through the blood vesselto the site of the occlusion, the heart, or any other area to betreated. Once the guide wire is in place, a working sheath can be slidover the guide wire to form a wider, more easily accessible, tractbetween the epidermis and the opening into the blood vessel If anangioplasty needs to be per formed, the balloon catheter can then beintroduced over the guide wire again through the working sheath, throughthe opening in the femoral artery, and then up to the blood vessel tothe site of the occlusion.

Once the procedure is performed, the guide wire, balloon catheter andany other equipment introduced can be retracted through the bloodvessel, out through the opening in the blood vessel wall, out throughthe working sheath, and out of the body entirely. The working sheath canthen be removed whereby the physician or other medical technician ispresented with the challenge of trying to close the opening both in thefemoral artery and the tissue tract formed in the epidermis andsubcutaneous tissue Most importantly, the opening in the blood vesselmust be closed as soon as possible.

Over the years that these procedures have been performed, a number ofapparatus and methods have been created fbi closing the opening in theblood vessel. Traditionally, and still commonly today, the opening isclosed simply by the application of manual pressure If sufficientpressure is applied, the blood vessel is constricted until a clot orthrombus forms whereupon the pressure can be removed and eventually thepatient can become ambulatory once again However, a number of drawbacksare associated with such a method For one, the process is very timeconsuming often taking many hours fbi the thrombus to fully form, duringwhich time the patient is required to be stationary. In addition, themere application of such significant pressure to the groin is oftenquite uncomfortable for the patient.

In light of these difficulties, a number of proposals have beenintroduced to potentially alleviate such drawbacks. In one approach, ananchor is inserted through the tissue tract and the blood vessel with afilament extending therefrom and connected to a sealing plug by a pulleyarrangement. Once the anchor engages an interior surface of the bloodvessel the filament can be used to pull the sealing plug securely intothe tissue tract. While this approach does more quickly close theopening in the blood vessel than manual pressure application, it alsoresults in the unfavorable characteristic of leaving a foreign body inthe patient after the procedure is completed.

Another approach uses a resistive heating coil inserted into the openingin the blood vessel. Upon energization of the heating coil, the blood inthe vicinity of the opening is caused to coagulate given the rise intemperature. This can be accomplished in combination with theintroduction of a procoagulant into the site to again expedite thecreation of the coagulation While this approach has also met with somelevel of success, it also results in the introduction of a foreign bodyand/or substance into the tissue of the patient.

A still further approach involves the introduction of a collagen pluginto the site of the opening. Such a plug is sized to be frictionallyengaged by the sides of the opening in the blood vessel and thus held inplace until coagulation of blood forms around the collagen plug. Thecollagen plug is biodegradable and eventually is dispersed into theblood flow and eliminated from the body. However, just the introductionof such a foreign substance into the body can sometimes be, at the veryleast, inflammatory and uncomfortable for the patient

In one collagen plug approach, a balloon catheter is inserted into theblood vessel, inflated, and then pulled back against an interior surfaceof the blood vessel wall to serve as a backstop. The collagen plug insuch an approach is shaped and sized as to closely match the opening inthe blood vessel wall and is pushed down into the tissue tract until itengages the inflated balloon. The inflated balloon can then be deflatedand withdrawn leaving the collagen plug in place.

In another collagen plug approach, a delivery sheath wider than theopening in the blood vessel wall is used and then a collagen plugcorresponding to the size of the inner diameter of the delivery sheathis pushed through the sheath so as to engage the outer surface of theblood vessel wall The plug can then be tamped or compressed down againstthe exterior surface of the blood vessel wall such that a portion of thecollagen extends into the opening of the blood vessel wall

While each of the foregoing approaches have been met with some level ofsuccess, it can be seen that each also has substantial drawbacks.Accordingly, it would be advantageous for the art to provide anapparatus and method which can quickly close the opening in the bloodvessel wall, minimizes any decrease in blood flow through the bloodvessel during the closure procedure, forms a thrombus which reliablyremains in place after formation, minimizes patient discomfort,introduces no foreign body or substance into the blood vessel and leavesno foreign bodies behind after the procedure is completed.

SUMMARY OF THE DISCLOSURE

According to one aspect of the disclosure, an apparatus is disclosed forclosing an opening in a blood vessel. The apparatus may include a sheathextending from the epidermis of a patient to a blood vessel, the sheathhaving a proximal end positionable at the epidermis of the patient and adistal end positionable at the blood vessel wall of the patient. Theapparatus further includes a balloon catheter inserted through thesheath with the balloon catheter having a proximal end positionable atthe epidermis of the patient and a distal end positionable within theblood vessel of the patient. The apparatus further includes first andsecond electrodes with the first electrode being at the proximal end ofthe sheath and balloon catheter, and the second electrode being at thedistal end of the balloon catheter.

In accordance with another aspect of the disclosure, an apparatus forclosing an opening in a blood vessel is disclosed which comprises amember for extending between an epidermis of a patient and a bloodvessel wall of a patient, a first electrode, and a second electrode. Themember includes a proximal end positionable at the epidermis and distalend positionable at the blood vessel wall with the first electrode beingat the member proximal end and the second electrode being at the memberdistal end.

In accordance with another aspect of the disclosure, a method of closingan opening in a blood vessel is disclosed comprising inserting a sheathinto a tissue tract of a patient extending between an epidermis and ablood vessel wall, extending a balloon catheter into the sheath, theballoon catheter having a shaft extending into a balloon, the ballooncatheter being inserted until the balloon is entirely within the bloodvessel, at least one of the sheath and balloon catheter having apositive electrode thereon, at least one of the sheath and ballooncatheter having a negative electrode thereon, inflating the balloon,retracting the balloon until the inflated balloon engages an interiorsurface of the blood vessel wall, and creating an electric field betweenthe negative and positive electrodes, cells thereby being attracted tothe positive electrode and forming a thrombus at the blood vessel wall.

In accordance with another aspect of the disclosure, a method of closingan opening in a blood vessel is disclosed which comprises inserting amember between the epidermis of the patient and the opening of the bloodvessel wall of the patient, the member having a positive electrode andnegative electrode thereon, and creating a electric field between thenegative and positive electrodes, cells thereby being attracted to thepositive electrode and forming a thrombus at the blood vessel wall. Themember includes proximal and distal ends with the distal end beingpositionable at the blood vessel wall, and the positive electrode beingprovided at the member distal end

These and other aspects and features of the disclosure will become moleapparent upon reading the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a blood vessel, subcutaneous layer,and epidermis layer with a tissue tract formed between the epidermis,through the subcutaneous layer, and to the blood vessel wall;

FIG. 2 is a sectional view similar to FIG. 1, but with a workingsheath/sleeve extended through the tissue tract;

FIG. 3 is a view similar to FIG. 2, but with an uninflated ballooncatheter being extended through the introducer sheath;

FIG. 4 is a view similar to FIG. 3, but with the balloon catheterinflated;

FIG. 5 is a view similar to FIG. 4, but with the balloon catheterinflated and retracted to be against the inner surface of the bloodvessel wall;

FIG. 6 is a view similar to FIG. 5, but with electrodes creating anelectric field and thereby drawing cells to the positive electrode;

FIG. 7 is a view similar to FIG. 6, after a thrombus has formed andprior to the balloon catheter and working sheath being retracted;

FIG. 8 is a view similar to FIG. 7, but with the thrombus fully formedafter the balloon catheter and working sheath are withdrawn;

FIG. 9 is a sectional view of an alternative embodiment depicting atoroidal-shaped balloon;

FIG. 10 is a sectional view similar to the previous views but depictinga self supporting balloon;

FIG. 11 is a sectional view of FIG. 10, taken along line 11-11 of FIG.10, showing the self-supporting balloon extending across the bloodvessel at two diametrically opposed points;

FIG. 12 a is a sectional view of an alternative embodiment using arolling membrane balloon and depicted in an un-deployed configuration;

FIG. 12 b is a sectional view of the alternative embodiment of FIG. 12 abut depicted in a partially deployed configuration;

FIG. 12 c is a sectional view of the alternative embodiment of FIG. 12 abut depicted in a deployed configuration;

FIG. 13 is a sectional view of another alternative embodiment showing aremoval sheath;

FIG. 14 is a sectional view of another alternative embodiment showing aneverting balloon; and

FIG. 15 is a sectional view showing another alternative embodimentincluding a sealing plug.

While the present disclosure is susceptible to various modifications andalternatives constructions, certain illustrative embodiments have beenshown in the drawings and will be described below in detail. It shouldbe understood, however, that there is no intention to limit the presentinvention to the specific forms disclosed, but on the contrary, theintention is to cover all modifications, alternative constructions, andequivalents falling within the spirit and scope of the presentinvention.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring now to the drawings and with specific reference to FIG. 1, ablood vessel 20 is depicted with an opening 22 therein after thecompletion of a medical procedure such as, but not limited to, a balloonangioplasty. As stated above with respect to the background, in such aprocedure, an opening or arteriotomy 22 is provided in a wall 23 of theblood vessel 20 to allow access into and passage through the bloodvessel of the various medical devices needed for the medical procedure.After such medical devices are used and removed from the opening andthrough a tissue tract 24 extending between a blood vessel 20 and asubcutaneous layer 26, and an epidermis layer 28, the opening 22 andtract 24 need to be closed. The pending disclosure is primarily directedto an apparatus and method for closing the opening 22 in the bloodvessel wall 23.

Referring now to FIG. 2, a first step according to the presentdisclosure is to insert a working sheath 30 into the tissue tract 24substantially to the opening 22 in the blood vessel wall 23. The workingsheath 30 may include a main cylindrical body 32. A circumferentialflange 34 can be movably located around the sheath 30 to provide aflange electrode located on the skin. Other electrode designs can alsobe used to allow for current flow. The working sheath 30 may be providedin any number of different forms and may or may not include the flange34 or could be provided with other indicia on the main body 32 informingthe physician or other medical technician the distance the workingsheath should be introduced into the tract 24. In addition, the workingsheath 30 may be slid along a guide wire (not shown) and extendedthrough the tract 24 and into the blood vessel 20. However, for thepurpose of illustration, and ease of understanding, the guide wire isnot depicted.

Referring now to FIG. 3, a next step is depicted where a ballooncatheter 36 is extended into the working sheath 30. The balloon catheterincludes a shaft 38 from which a balloon 40 extends The balloon catheter36 is extended through the working sheath 30 in an uninflated state. Theballoon catheter 36 is extended to a distance necessary to allow theballoon 40 to be fully received within the blood vessel 20.Alternatively, the apparatus could work in conjunction with aconventional introducer sheath wherein the balloon catheter is slidthrough an introducer sheath and the working sheath is then slid throughthe introducer sheath In such an embodiment, the negative electrodementioned later herein could be located in the working sheath.

Referring now to FIG. 4, it is seen that the balloon 40 is theninflated, i.e., by the introduction of air or fluid into the balloonshaft and ultimately the interior of the balloon 40. The balloon 40 isof such a size that even when inflated, blood flow through the bloodvessel 20 is not fully occluded, but does allow for a certain degree ofperfusion therethrough. After the balloon 40 is fully inflated, theballoon catheter 36 is retracted away from the center of the bloodvessel 20 such that an upper surface 41 of a balloon 40 engages an innersurface 42 of the blood vessel wall 23 In so doing, it will be readilyunderstood by one of ordinary skill in the art that the opening 22 issubstantially sealed preventing any significant level of blood flowbetween the blood vessel 20 and the tissue tract 24.

Once the physician reaches the position depicted in FIG. 5, asdetermined based on the degree of resistance felt when retracting theballoon 40 and lack of blood flow out of the tissue t act 24, thephysician or other medical technician can energize first electrode 44and second electrode 46. In so doing, an electric field 48 is createdbetween the first and second electrodes 44 and 46 as shown in FIG. 6. Inaddition to the layout of FIG. 6, additional electrode configurationsare available within the scope of this disclosure to create multiplefields and further aid in thrombus formation By positioning theelectrodes appropriately, the blood cells within the tissue tract 24 areattracted to a position where it is desired to have a thrombus 50 formedMore specifically, the platelets of the blood are attracted to thepositive electrode, even in blood which has been treated with a bloodthinner or other anti-coagulant, such as heparin Since such blood cellsare attracted to a positive electrode, by positioning the positiveelectrode appropriately, a thrombus can be formed in a desired locationThus in the depicted embodiments, the first electrode 44 is negativelycharged and the second electrode 46 is positively charged, with thesecond electrode being provided at a position proximate the blood vesselwall 23 The thrombus 50 is therefore formed as shown in FIGS. 6, 7, and8 at the juncture between the blood vessel wall 23 and the tissue tract24 Alternatively, the positively charged electrode can be located alongthe shaft of the balloon catheter, at the distal end of the shaft, or ona portion of the balloon. By the same token, the negative electrode canbe located on the skin of the patient.

After the thrombus 50 fully forms in the tract 24 around the shaft 38,the balloon 40 can be deflated and fully withdrawn through a centeropening 52 within the thrombus 50 as shown in FIG. 7. The working sheath30 can be removed at the same time as well. A minimal amount of manualpressure or bandaging 53 can then be provided over the tract 24 tominimize blood loss until the opening 52 within the thrombus 50 fullycloses as shown in FIG. 8. Using such a method, it has been determinedthat the closure of the opening 22 can be accomplished in less then fiveminutes at relatively low voltages and amperages, thus minimizing thediscomfort to the patient as well. In addition, in order to lessen thelikelihood of the thrombus being dislodged when the balloon 40 isretracted, a tank tread or rolling membrane balloon may be employed asdepicted in FIGS. 12 a-12 c and described in further detail herein.

Referring again to FIGS. 5 and 6, it can be seen that more than one setof positive and negative electrodes are depicted. A first set ofelectrodes 44, 46 may be provided at proximal and distal ends of theballoon catheter 36, with a second set of electrodes 44 a and 46 a beingprovided on proximal and distal ends of the working sheath 30. Othercombinations of one electrode on one element, and one electrode onanother element ate possible as well. In addition, as the positiveelectrode is of importance in dictating the location of the resultingthrombus, if more than one thrombus is desired it is possible toposition one positive electrode at a distal end of the balloon catheteror working sheath 30, and a second positive electrode at a position onthe balloon catheter or working sheath closet to the negative electrodethan the first positive electrode. Accordingly, a second thrombus (notshown) can be formed at an intermediate position within the middle ofthe tissue tract 24 for example as a secondary means of closure if it isdesired In such an embodiment, it would be possible to only provide asingle negative electrode with that one single negative electrodecreating electric fields between it and both positive electrodes.

Referring now to FIGS. 9-11, alternative embodiments of the balloon aredepicted. In order to facilitate the formation of the thrombus 50, theinventors have found that it is beneficial to create a pocket 54 betweenthe upper surface 56 of a balloon 58 and the inner surface 42 of theblood vessel wall 20. The pocket 54 forms a natural recess into whichthe thrombus 50 can be formed when the electrodes are energized. Inorder to form the pocket 54 one version of the balloon 58 is provided ina toroidal shape in cross section.

In addition to the pocket 54, it may be beneficial to provide“self-supporting” balloon such as that depicted in FIGS. 10 and 11 Asshown therein, the balloon 60 has a substantially T-shaped configurationin cross-section having an upper expanse 62 from which a leg 64 extends.The balloon 60, including its expanse 62 and leg 64 has a dimension soas to extend across the entire diameter of the blood vessel 20 andcontact the inner surface 42 of the blood vessel 20 in at least twodiametrically opposed locations denoted as points 66 and 68 in FIGS. 10and 11. As also depicted in FIG. 11, it can also be seen that theT-shaped configuration of the balloon 60 does not substantially occludethe flow of blood through the blood vessel 20, but rather provides amplespace 70 for such blood flow even when balloon 60 is inflated Such a“self-supporting” balloon provides significant strength as a backstop inthat it engages the rear of the blood vessel, as well as the wall of theblood vessel proximate the opening Alternatively, the self-supportingballoon can be teardrop-shaped among other shapes.

Referring now to the aforementioned FIGS. 12 a-12 c, a rolling membraneballoon 80 is depicted. The previously mentioned balloons can be thoughtof as “pre-formed” balloons having a balloon located at a distal end ofa straight shaft. The balloon is inserted in a deflated condition,inflated, used as a backstop and locator while the thrombus is formed,deflated, and then retracted from the tissue tract. While effective, ifit is desired to reduce the pulling force applied to the thrombus as theballoon catheter is retracted, and thus lessen the likelihood of thethrombus being dislodged thereby, the rolling membrane balloon can beused. With such a rolling membrane, the balloon 80 can be extended froma shortened, rolled-up configuration depicted in FIG. 12 c to theconfiguration of FIG. 12 b and ultimately to the configuration of FIG.12 a This extension and retraction can be achieved through the use ofpressurized fluid and/or a mechanical rod. As shown in the figures, theballoon 80 may be connected to a manifold 82 and in turn to apressurized fluid source 84 When the source 84 is in communication withthe balloon 80, the balloon is caused to “roll-out” much like a tanktread from the position shown in FIG. 12 c to that depicted in FIG. 12a. In turn when the balloon 80 is to return to the position shown inFIG. 12 c, the balloon “rolls-up” thereby peeling away from the surfaceof the thrombus gradually, as opposed to simultaneously. This reductionin force may allow the thrombus to more likely remain in position. Asshown, a push/pull or withdrawal rod 86 may be used to manually extend(roll-out) and retract (roll-up) the balloon 80 as opposed to relyingsolely on fluid pressure

Two other approaches which can be used to facilitate removal of theballoon are depicted in FIGS. 13 and 14. In FIG. 13, a sheath 100 isplaced in close proximity to the shaft 38 of the balloon so as to aidremoving the balloon without disrupting the thrombus 50. In FIG. 14, aneverting balloon 140 is shown The balloon 140 is similar to balloon 40but for having a fiber or filament 142 extending through the shaft 138and being connected to a bottom wall 144 of the balloon 140.Accordingly, when the filament 142 is pulled out of the patient in thedirection of arrow 146, the balloon everts on itself, pulling away fromwithin and peeling its outer surface 148 gradually away from thethrombus

In any of the foregoing embodiments, the thrombus may be even moreeffectively formed by using a heat source in combination with theelectrodes In such embodiments a resistive coil 88 or the like can bepositioned at the distal end of one of the components of the apparatus,with coil 88 being shown as attached to the rod 86 in FIGS. 12 a-12 c asan example. The resulting rise in temperature of the blood andsurrounding tissue facilitates coagulation as well Thrombus formationmay also be aided by adding a biodegradable plug 200, such as collagenor fibrin, as shown in FIG. 15. The plug 200 could be positioned at ajunction 202 of the subcutaneous tissue 26 and the blood vessel wall 42In so doing, a surface for the thrombus 50 to attach to is provided Thevolume of material forming the plug 200 will reduce the time needed tocreate the thrombus mass adequate to ensure hemostasis and preventhematoma.

With respect to the parameters of the electrical field generated by theelectrodes, the inventors have found that the clot formation rate isdependent on a number of parameters including the type, intensity,duration, and other stimulation parameters of the electrode design. Inaddition, based on other requirements such as the time allotted for thethrombus to form, the size of the clot to form, the size of the wound toclose, the contact impedance, etc, the electrical stimulation signal canbe modified or chosen. For example, the electric field may be analternating current, direct current, pulsed alternating current orpulsed direct current The intensity of the field can be adjusted basedon amplitude, net energy, charged delivery, frequency, duty cycle, orother parameters. One particularly effective approach the inventorsfound was to use a DC positive signal continuously delivered to thethrombus site. The rate of clot formation increased with increasedamplitude of the signal.

Based on the foregoing, it can be seen that the present disclosureprovides an apparatus and method for effectively closing an opening in ablood vessel through the creation of an electric field in the area ofthe opening By appropriately positioning the positive electrode forminga portion of the electric field, blood cells are attracted to thepositive electrode and a thrombus is quickly formed thereabout.

1. An apparatus fbi closing an opening in a blood vessel, comprising: a balloon catheter having a proximal end positionable at an epidermis of the patient, and a distal end positionable at a blood vessel wall of the patient; a first electrode positioned on tissue of the patient distant from the opening in the blood vessel; and a second electrode at the distal end the balloon catheter
 2. The apparatus of claim 1, further including a sheath extending from the epidermis of the patient to the blood vessel wall, the sheath having a proximal end positionable at the epidermis of the patient, and a distal end at the blood vessel wall of the patient
 3. The apparatus of claim 1, wherein the first electrode is negatively charged and the second electrode is positively charged.
 4. The apparatus of claim 1, wherein the balloon catheter includes a balloon at the distal end, the balloon being toroidal in cross-section shape
 5. The apparatus of claim 4, wherein the balloon forms a pocket against an interior surface of the blood vessel wall, the pocket facilitating formation of a thrombus.
 6. The apparatus of claim 1, further including a second set of positive and negative electrodes.
 7. The apparatus of claim 3, further including a second positive electrode, the second positive electrode being positioned on one of the balloon catheter and the sheath at a distance closer to the negative electrode than the first positive electrode
 8. The apparatus at claim 1, wherein the balloon catheter includes a balloon at the distal end, the balloon being substantially T-shaped in cross-section
 9. The apparatus of claim 1, wherein the balloon catheter includes a balloon at the distal end, the balloon being substantially teardrop-shaped
 10. The apparatus of claim 1, wherein the balloon catheter includes a balloon adapted to extend between diametrically opposed interior surfaces of the blood vessel while still allowing perfusion through the blood vessel
 11. The apparatus of claim 1, wherein the first and second electrodes are formed by one of coiled wire, metal bands, foil, conductive ink, and gold micro-extrusion
 12. The apparatus of claim 1, wherein the balloon is a tolling membrane balloon.
 13. The apparatus of claim 1, further including a heat-source at the distal end of one of the sheath and balloon catheter
 14. An apparatus for closing an opening in a blood vessel, comprising: a member for extending between an epidermis of a patient and a blood vessel wall of the patient, the member including a proximal end positionable at the epidermis, and a distal end positionable at the blood vessel wall; a first electrode at the member proximal end; and a second electrode at the member distal end.
 15. The apparatus of claim 10, wherein the first electrode is negatively charged and the second electrode is positively charged.
 16. The apparatus of claim 10, further including a backstop at the member distal end.
 17. The apparatus of claim 16, wherein the backstop is a balloon.
 18. The apparatus of claim 16, wherein the backstop is a membrane covered wall
 19. The apparatus of claim 17, wherein the balloon is a lolling membrane balloon.
 20. The apparatus of claim 17, wherein the balloon is substantially toroidal in cross-sectional shape.
 21. The apparatus of claim 17, wherein the balloon is substantially T-shaped in cross-section.
 22. A method of closing an opening in a blood vessel, comprising: inserting a sheath into a tissue tract within a patient extending between an epidermis and a blood vessel wall; extending a balloon catheter into the sheath, the balloon catheter having a shaft terminating in a balloon, the balloon catheter being inserted until the balloon is fully within the blood vessel, one of the sheath or balloon catheter having a positive electrode thereon, one of the sheath and balloon catheter having a negative electrode thereon; inflating the balloon; retracting the balloon catheter until the inflated balloon engages an interior surface of the blood vessel wall; and creating an electric field between the negative and positive electrodes, blood cells thereby being attracted to the positive electrode and forming a thrombus at the blood vessel wall
 23. The method of claim 22, wherein inflating and retracting the balloon causes a pocket to form between the balloon and the blood vessel wall.
 24. The method of claim 22, wherein inflating the balloon causes the balloon to engage the blood vessel wall at at least two diametrically opposed points
 25. The method of claim 22, wherein the balloon is self-supporting when inflated.
 26. A method of closing an opening in blood vessel, comprising: inserting a member between an epidermis of a patient and the opening of the blood vessel wall of the patient, the member having a positive electrode and negative electrode thereon; and creating an electric field between the negative and positive electrodes, blood cells being attracted to the positive electrode and forming a thrombus at the blood vessel wall.
 27. The method of claim 26, wherein the member is a balloon catheter.
 28. The method of claim 26, wherein the member is a rolling membrane balloon
 29. The method of claim 28, wherein the rolling member is inserted by directing a pressurized fluid into the rolling balloon
 30. The method of claim 28, wherein the rolling membrane balloon is inserted and retracted using a mechanical extension and withdrawal rod.
 31. The method of claim 26, wherein the member is a working sheath.
 32. The method of claim 31, further including extending a balloon catheter through the working sheath until a balloon extending from a shaft of the balloon catheter is fully within the blood vessel, inflating the balloon, and retracting the balloon until it engages an interior surface of the blood vessel wall, before the electric field is created.
 33. The method of claim 32, further including forming a pocket between the balloon and the blood vessel wall to facilitate formation of the thrombus.
 34. The method of claim 32, further includes inflating the balloon such that it engages at least two diametrically opposed points on the interior surface of the blood vessel wall.
 35. The method of claim 26, further including heating the distal end of the member. 